1. Field of the Invention
The present invention relates generally to the field of valves, and more particularly, to a stemless ball valve that utilizes a planetary gear assembly to increase torque from the valve handle to the ball.
2. Description of the Related Art
The present invention represents an evolution in ball valve technology beginning with the stemless ball valve disclosed in U.S. patent application Ser. No. 12/331,387, wherein the ball is actuated by an outer magnetic cartridge in magnetic contact with an inner magnetic cartridge that rotates a guide sleeve. The guide sleeve has guide channels into which travel pins on the ball are inserted. The guide channels are shaped and the travel pins are situated so that as the guide sleeve rotates, the travel pins travel inside the guide channels, thereby rotating the ball.
The next related evolution in stemless ball valve technology is represented by the invention disclosed in U.S. patent application Ser. No. 12/890,645. In this invention, the guide sleeve that was situated inside of the inner magnetic cartridge is moved so that it is adjacent to and outside of the inner magnetic cartridge but secured to the inner magnetic cartridge so that when the inner magnetic cartridge rotates, the cartridge guide holder also rotates. The guide sleeve is situated inside of the cartridge guide holder and comprises guide channels into which the travel pins on the ball are inserted. Thus, the ball is rotated in the same manner as in the previous invention, except that a larger ball can be used because the cartridge guide holder and guide sleeve are no longer inside of the inner magnetic cartridge, but adjacent to it. The larger ball allows for a valve with greater flow capacity.
Although the two inventions described above solve many of the problems associated with stemmed ball valves, one major drawback of these valves is that they have not been able to match the torque requirements of stemmed valves. In addition, magnetically-actuated valves tend to experience hysteresis, which is a lag that occurs between the outer and inner magnetic cartridges and that becomes more pronounced as the torque required to power a given valve element approaches the maximum torque available from the magnetic drive. When hysteresis is pronounced, slippage may occur between the inner and outer magnetic cartridges, causing the valve to malfunction.
Stemless ball valves are desirable over stemmed valves because there is no penetration from outside of the valve into the valve body. This lack of penetration from the outside reduces emissions and prevents leakage. Until now, the torque of stemless ball valve designs was limited by the torque that could be provided by the magnetic interlock between the inner and outer magnetic cartridges. What was needed was a stemless ball valve that could provide the same torque as a stemmed valve while still providing a leak-free environment.
As described more fully below, the present invention solves this problem by interposing a planetary gear assembly between the inner magnetic cartridge and the ball. This planetary gear assembly greatly increases the torque from the handle outside of the valve (the handle being coupled to the outer magnetic cartridge) to the ball itself, thereby allowing the valve to operate effectively in applications that require higher torque, while still providing the advantages of a stemless ball valve.